Systems comprising shafts which are constructed for slideable linear motion in cylindrical bearings are subject to a high degree of friction, and wear, binding and chatter because of misalignment, which lead to lubrication and maintenance problems.
In the prior art, an attempt has been made to reduce or eliminate some of the problems in such systems by using one or more oblong re-circulating ball circuits or Roundway bearings which circulate in the longitudinal direction of the shaft.
Such prior art systems have certain disadvantages, in that they are heavy, requiring a substantial amount of additional material; and the circulating ball or roller trains retain dirt and foreign particles. Furthermore, they exert extreme pressures at the points of contact on the shaft which cause what is known as `brinelling` in which the material of the shaft flakes away.